It is now well established that aggregation plays a central role in cataract formation. Our principal research objective is to identify the biochemical origin and physical structure of these aggregates. From the biochemical point of view, we shall identify the exact proteins and proetin-protein interactions associated with the formation of the heavy molecular weight protein components (HM) in normal and cataractous human lenses. From the physical point of view, it was recently discovered that the diffusivity of proteins in the intact lens can be measured using the method of quasielastic light scattering spectroscopy. From the diffusivity measurements we may determine the size of the protein aggregates both in the intact lens and in solution in order to help identify the role of various biochemical agents in the formation of cataract. BIBLIOGRAHIC REFERENCES: R.J. Cohen, J.A. Jedziniak, and G.B. Benedek, Study of the Aggregation and Allosteric Control of Bovine Glutamate Dehydrogenase by Means of Quasi-Elastic Light Scattering Spectroscopy, Proc. R. Soc. Lond. A. 345, 73 (1975).